One person was killed and three injured in a stabbing attack at a shopping centre in Beaverton, near Portland, Oregon on Wednesday.
A suspect is a 20-year-old man, according to police. The agents work on the scene to investigate the details of the crime.
The rescue services staff arrived at the scene to provide the first aid and shortly sent the injured to the local trauma centre.
During a press briefing, Mayor of Beaverton Denny Doyle connected the attack to "mental health issues" and urged his colleagues to change the approach to tackling a rise of violence in various US localities. "This is definitely going too far. We have to address it", he said.
"All our crews were on scene here treating the patients here, they are also dispatched to the incident where the second car jacking occurred. There was a patient at that location that was treated by our crews and was also transported to a local trauma centre," Doyle said.
"Our thoughts go out to the victims and their families involved in this tragedy, and we do not have any information about their condition at this time," he added.